Check valve

ABSTRACT

The specification and drawings disclose poppet-type check valves each comprising a body with a through flow passage and a valve member with a generally circular sealing surface positioned within the passage. The valve member is continually biased toward a seat by a coil spring mounted in the passage. An O-ring positioned in a circumferential groove formed about the passage defines the seat. The groove is open only about the axial side facing the valve member. The inner circumference of the groove is of a lesser diameter than the sealing surface of the valve member. The O-ring is positioned within the groove and has a radial thickness sufficiently greater than the radial width of the groove such that when compressed in the groove, a portion extends out of the open side for engagement with the end face of the valve member. The radially inner wall of the groove is provided with a continuous edge surface which is adapted to engage the end face of the valve member to provide a fixed stop for the valve member. Means for varying the compression on the spring are provided and includes two members threaded axially in the passageway. Each of the members is shown as having a noncircular flow passageway formed through its center. The passageways align in certain positions of relative rotation for adjustment purposes. Thus, adjustment can be accomplished by insertion of an adjusting tool into the flow passage and no external adjustment members are required.

United States Patent [1 1 Gallagher et a1.

[ CHECK VALVE Ohio [73] Assignee: Nupro Company, Cleveland, Ohio [22Filed: Oct.1 4, 1971 211 App]. No.: 189,208

[52] US. Cl l37/5l6.29, 137/541, 137/541.21,

267/175 [51] Int. Cl. F16k 15/02 [58] Field of Search 137/516.25,516.27,

56 References Cited UNITED STATES PATENTS 2,021,771 11/1935 Farmer137/540 X 2,940,472 6/ 1960 Chilcoat 137/540 992,137 5/1911 Nowak 151/201,832,060 11/1931 Strid 151/20 1,360,960 11/1920 Kudla l3 7/516.25 I2,745,432 5/1956 Williams 137/540 2,859,031 ll/1958 Hansen et a1l37/543.2l X 2,959,188 11/1960 Kepner 137/540 3,189,046 6/1965 Callahanet a1.... 137/540 X 3,255,774 6/1966 Gallagher et al. l37/516.29

FOREIGN PATENTS 0R APPLlCATlONS 2,532 1898 Great Britain 137/540 731,0286/1955 Great Britain 137/540 [111 3,754,568 [451 Aug. 28, 1973 PrimaryExaminerWi1liam R. Cline AttorneyFay, Sharpe & Mulholland [57] ABSTRACTThe specification and drawings disclose poppet-type check valves eachcomprising a body with a through flow passage and a valve member with agenerally circular sealing surface'positioned within the passage. Thevalve member is continually biased toward a seat by a coil springmounted in the passage. An O-ring positioned in a circumferential grooveformed about the passage defines the seat. The groove is open only aboutthe axial side facing the valve member. The inner circumference of thegroove is of a lesser diameter than the sealing surface of the valvemember. The O-ring is positioned within the groove and has a radialthickness sufficiently greater than the radial width of the groove suchthat when compressed in the groove, a portion extends out of the openside for engagement with the end face of the valve member. The radiallyinner wall of the groove is provided with a continuous edge surfacewhich is adapted to engage the end face of the valve member to provide afixed stop for the valve member. Means for varying the compression onthe spring are provided and includes two members threaded axially in thepassageway. Each of the members is shown as having a non-circular flowpassageway formed through its center. The passageways align in certainpositions of relative rotation for adjustment purposes. Thus, adjustmentcan be accomplished by insertion of an adjusting tool into the flowpassage and no external adjustment members are required.

12 Claims, 11 Drawing Figures CHECK. VALVE lems with this arrangementhas been, the difficulty of properly holding the seat in position. Attimes, line pressure can get behind the seat member andcause it toblow-out. Additionally, under high back pressures, the poppet canbedriveninto the resilient seat, damaging the seat or otherwise injuringthe valve.

A further problem with the prior poppet-type checkvalves has been thatwhen subjected to high and sudden pressure surges, the compression orcontrol spring could be over stressed-and damaged; Moreover, undercertain conditions, some of the prior compression springarrangementscould'cause the poppet to jam in the open position.

Another difficulty with prior valves of the type under consideration'wasthat they couldnot be readily ad justedfor different pressure settings.Many could only be adjusted by changing springs. Others, althoughdesignedto permit the compressionon the spring to bevaried; wereextremely difficult to adjust. Often, special tools or substantialdisassembly of the valve was re.- quired. Even then, it was very hard tochange the compression on the spring and lockthe adjusting mechanism atthe desired'position.

The subject invention seeks to overcome the abovediscussedproblems by.the. provision of a poppet-type checkvalve having a body with a'throughflowpassage and a valve member having a generallycircular sealingsurface is positioned within the passage and continually biased toward aseat. According to one aspect of the invention, the seat is-defined byan O-ring positioned in a circumferential groove formed about thepassage. The groove is open only about the axial side facing the valvemember. The inner circumference of the groove is of a lesserdiameterthanthe sealing surface of the valve member. The O-ring is positioned withinthe groove and-has a radial thickness sufficiently greater than theradial width'of the groove such that when compressed in the groove, aportion extends out of the open side for engagement with the end face ofthe valve member. The radially inner wall of the groove is alsopreferably provided with a continuous edge surface which is adapted toengage the end face of the valve member to provide a fixed stop. Bycontrolling the size of, the groove and the O-ring, the totalsealingpressure between the O-ring and the valve member is controlled.

.The invention also contemplates that the O-ring receiving groove willhave a continuous radially extending lip about its inner wall to providea band of high contact pressure between the O-ring and the groove. Thishelps retain the O-ring in the groove and prevents fluid pressure fromgetting behind the O-ring.

Another aspect of the invention contemplates that biasingmeans willcomprise a coil spring positioned within the passage between the valvemember and an adjustable stop. The adjustable stop includes at least twomembers threaded axially in the passageway. The innermost serves as thetop and the outermost serves to lock the stop in its adjusted position.Each of the members has a flow passageway formed through its center. Themembers include tool receiving portions and align in certain positionsof relative rotation. For example, in the preferred embodiment, thepassageways are hex shaped. Consequently, to adjust the position of thestop, an Allen wrench is inserted into the passageway until it engagesthe hex shaped passageway in the lock member. The lock member can thenbe rotated to release it from its lock position and align its passagewaywith the passageway in the stop member. The wrench can-thenbe insertedfurther in to engage the stop member. Thereafter, the stop member can berotated simultaneously with the lock member to move it to a new positionof adjustment. Subsequently, the above procedure is reversed to'lock thestop member in position.

The described compression spring adjustment is both simple and reliable.As is apparent, the adjustment members do not extend externally of thevalve body and disassembly of the valve is not required to effect theadjustment. Further, in the preferredembodiment, no special tools arerequired for making the adjustment.

Accordingly, one primary object of the invention is the provision of arelatively simple, compact check valve which is easy toadjust.

Another object is the provision of a check valve of the general typedescribed wherein the seat includes an O-ring type seal which, inaddition to serving as a seat member, seals mating body sections.

A still further object is the provision of a check valve of the generaltype described wherein the movement of the valve member is limitedbetween fixed stops and guided throughout its movement.

An additional object is the provision of a check valve of the generaltype described which can be adjusted to different pressure settingswithout special tools or disassembly.

The above and other objects and advantages will become apparent from thefollowing description when read in conjunction with the accompanyingdrawings wherein:

FIG. 1 is a side view partially in cross-section of a check valve formedin accordance with the preferred embodiment of the invention; I

FIG. 2 is an enlarged cross-sectional view of the cir cled area of FIG.1;

FIGS. 3 and 4 are partial cross-sectional views of the left-hand end ofthe valve of FIG. 1 showing the adj'ust able stop mechanism;

FIGS. 5 and 6 are end views taken on lines 55'and 6-6 of FIGS. 1 and 3respectively;

FIG. 7 is a side view partially in cross-section showing a modified formof the invention;

FIG. 8 is an enlarged cross-sectional view of the poppet and valve seatof the valve of FIG. 7;

FIG. 9 is a longitudinal cross-sectional view through a modified form ofthe FIG. 7 embodiment;

FIG. 10 is a view taken on line l010 of FIG. 9 showing the left end ofthe FIG. 9 valve; and, r

FIG. 11 is a view of the left end of the valve of FIG. 7 but showing thestop and adjustment members in position for adjustment of the springcompression.

Referring more particularly to FIG. I, the preferred embodiment of theinvention is shown as comprising a one-piece body having an axiallyextending flow passage 12 in which is carried the valve and seatassembly l4 and the setting adjustment assembly 16.

In the embodiment under consideration, the body 10 is, as previouslymentioned, a one-piece body formed from any suitable material and hasthe general circular flow passage 12 formed axially therethrough. Thebody is shown as having pipe threads 18 and 20 formed on opposite endsso that the valve may be readily connected into standard piping systems.Other types of connecting arrangements, such as flanges, swage fitting,or the like, could obviously be used instead of the threaded ends shown.Preferably, the center section of the body 10 is provided with wrenchflats 22 to assist in installation or removal of the valve.

One aspect of the subject invention which is relatively important is therelationship between the valve member and the seat assembly. As shown,the assembly comprises a poppet type valve member 24 which is slidablymounted in section 26 of the passage 12. The valving portion of themember 24 includes a somewhat conically shaped end 28 having a generallyflat face 30 and an inclined peripheral edge portion 32. A cylindrical,tubular portion 34 is joined to portion 28 by a continuous, inclined endwall 36. A plurality of openings 38 are formed through the end wall 36in the manner shown. It should be noted that the openings 38 arepreferably inclined at an angle generally corresponding to the taper onthe conical end portion 28 so that a relatively smooth flow path isprovided through the member and about the end portion.

The seat assembly for the valve member 24 is, in the preferredembodiment, releasably carried in the righthand end of the valve andincudes a seat retainer member 40. Member 40 is, as best shown in FIG.2, slidably received in a counterbore 42 formed in passageway 12. Athrough passage 44 is formed throughthe retainer 40 and has a diametersubstantially less than the maximum diameter of end portion 28 of thevalve member 24. The retainer member 40 is locked in position in thebody by a lock member 45 threadedly received in the outer end of thepassageway 12. The lock member 45 has a center passageway 46 which ispreferably of noncircular shape so that a wrench or other tool can beinserted into the passageway for removal of the lock member. In theembodiment shown, passageway 46 is hex shaped so that a standard hexwrench can be used for this purpose.

The retainer member 40 includes an axially extending flange portion 48which, in combination with the inner surface of the wall of passageway12 defines an annular, axially open recess 50. A protuberance or lip 52extends radially outward from the surface of flange portion 48. It willbe seen that the flange portion 48, lip 52, and the inner wall ofpassageway portion 26 confine a resilient O-ring throughout an extent ofgreater than 180 degrees of its cross-sectional circumference.- TheO-ring is sized so that in the uncompressed state, its internal diameteris substantially less than the diameter across the retainer over the lip52. Additionally, its outer diameter is preferably greater than theinternal diameter of the passage portion 26. Thus, when compressed inthe recess 50, it will normally extend axially out of the recess asillustrated by the dotted line 54. Thus, the plug member 24 sealinglyengages the O-ring when it is in the closed position shown. The totalcompressive load that can be applied to the O-ring seat is, of course,limited by the flange 48.

Because of the manner in which the O-ring is confined, fluid frompassageway 12 cannot get behind it and move it out of the recess.Additionally, it should be noted that the retainer 40 has inclined endfaces 58 and 59 which engage a rounded shoulder portion 60. When thelock member 45 is tightened, the faces 58 and 59 and the shoulder 60provide metal-to-metal seals to prevent entrance of fluid from the inletside of the valve member.

In the embodiment under consideration, the valve member 24 iscontinually biased toward the seat by a coil spring 62. The springpreferably has an outer diameter such that it is closely received withinthe tubular portion 34 of the valve member. The opposite end bearsagainst the adjustable stop assembly 16. It should be noted that ashoulder 63 is formed within the passageway 12. The shoulder acts as astop for the valve member and limits the extent of opening.

Although the adjustable stop assembly 16 could take many forms withinthe scope of the invention, in the subject embodiment, it comprises afirst movable stop member 64 and a lock member 66 which are threadedlyreceived in the left-hand end of the body 10. As shown, the passageway12 is provided with internal threads 68 which receive the stop member 64and the lock member 66 and permit them to be shifted longitudinally inthe passageway. Both the adjustable stop member 64 and the lock member66 have axial passageways which provide a flow path through the stopassembly. As will hereafter become apparent, the axial passagewaysthrough these members could have many different configurations. However,in the embodiment shown, the passageways are hex shaped and of the samesize. Thus, the stop member 64 can be threaded into the body to adesired position by the use of a standard hex wrench. Thereafter, thelock member can be threaded in to lock the stop member in the desiredposition. When assembled, the stop member and lock member will normallynot have their hex passages in alignment. For example, see FIG. 5, whichillustrates the stop and lock members in'a lock position with the hexportions out of alignment. To adjust the setting of the adjustable stopmember 64 after assembly, a hex wrench is inserted into member 66 andthe member loosened only slightly to bring the two hex openings intoalignment as shown in FIGS. 6 and 3. This releases the lock member fromthe adjustable stop member and as soon as the hex portions are inalignment, the wrench can be inserted further in to engage with theadjustable stop member 64. Thereafter, rotation of both members can takeplace simultaneously to adjust the location of the stop member and thecompression onspring 62. FIG. 4 shows the stop member and the lockmember adjusted to a new position. Their spacing is, of course,maintained uniformly throughout adjustment and when the desired positionof adjustment is reached, the wrench is withdrawn to a position where itengages only the lock member 66. The lock member can then be tightenedto hold the stop member in the desired position. The entire adjustmentcan thus take place without removal of any components and without theuse of special tools. It should be understood that although the twopassageways through the lock and adjustment members have been describedand illustrated as hex shaped, they could have substantially any desirednon-circular shape. Further, although they have been illustrated as ofuniform size, they could be of different size. Further, tool receivingslots, openings or the like could be provided for alignment only incertain positions of relative rotation. This would allow use of circularopenings through the members but would normally require a special toolor additional machining operations and is less desirable.

Although the members 64 and 66 can, in many instances, be in directengagement, some combinations of materials for the body and adjustmentmember result in low'friction between the body and adjustment member.Consequently, under some conditions, final tightening of the lock membercan rotate the adjustment member slightly to move it out of position.For this reason, it is preferable to reduce frictional contact betweenthe adjustment and lock members. For example, in the subject embodiment,a washer 67 is placed between members 64 and 66. The washer 67 serves asa bearing to eliminate the possibility of moving member 68 duringtightening. As will subsequently become apparent, other types of bearingmeans, low friction surfaces or the like could equally well be used.

To change compression springs, the lock member and the adjustable stopmember can be rapidly removed allowing the compression spring member tobe moved through the left-hand end of the passageway 12. Similarly, thevalve member can be removed merely by removing the lock member 45 andthe retainer 40 together with the O-ring 54.

FIGS. 7 and 8 illustrate a modified form of the invention whichincorporates the same main features described with reference to theFIGS. 1 through 6 embodiment. In general, the FIGS. 7 and 8 embodimentdiffers in that it comprises a two-piece housing 100 including a firstmale-body section 102 which is threadedly received in a female bodysection 104.-The male body section 102 has a central flow passagel06which extendsaxially therethrough. The left end of passage l06'isprovided with an opening 108 of the type used for swage connectors.Thefemale body section 104 is similarly provided with a through passage110 and a threaded counterbored section 112 which receives the maleportionof bodyv section 102..

The valve and seat assembly 114 is formed generally similar to thatdescribed with reference to the FIGS. 1 through 6 embodiment. Inparticular, it comprises a valve member 116 which is identical in shapeto valve member 24 of the first embodiment. The primary difference inthe valve and seat assembly of FIGS. 7 and 8 embodiment lies in theretaining arrangement for the O-ring seat member. As shown, an axiallyextending circumferential recess 118 is formed in the end wall of thecounterbore 112. An O-ring I is positioned within the recess. Asbestshown in FIG. 8,'the Oring is sized so that it is compressed withinthe groove and has a portion which extends outwardly beyond the innerwall 122 of the recess. Note that when the plug member 116 is in theopen position, the recess extends outwardly to the dotted line positionidentified by the numeral 122'.

The inner end of the male stem portion of body section I02 is arrangedto engage the O-ring and compress a portion of it upon tightening of thetwo body sections. Thus, in this embodiment, the O-ring is engagedthroughout an extent of greater than 180 degrees and is prevented fromblowing out. Moreover, the inner wall 122 of the recess serves as afixed stop so that the sealing pressure applied to the O-ring is limitedand the valve member prevented from extending into the seat uponoccuranceof a high back pressure.

The valve member 116 is maintained under a continual bias toward theseat by a compression spring 124 which is received within the circularcollar I26 of the valve member. The valve member 116 is limited in theextent of its opening by a snap ring received ina" justing member 138during tightening of the lockmemher 136. Adjustment of this embodimentis accomplished in the same manner as described with reference to theFIG. 1 embodiment. It is important to note, however, that the members136 and 138 are inserted from the right-handend of the passageway 106.For this reason, the maximum outer diameter over the apex of theirthreads must beless than the minimum diameter of the unthreaded, rightend portion of the passageway The FIGS 9 through 11 embodiment isgenerally the same as the embodiment shown in FIGS. 7 and 8'.Accordingly, the same reference numerals differentiated by the additionof a prime.() suffix have been used to identify the same elements.The'description of a FIG.

7 element is to be taken as equally applicable to the" correspondingelement of FIGS. 9 through 11 embodiment unless otherwise noted. Theprimary differences between the two embodiments reside in thearrangement of the seat and adjustment members. In the FIGS. 9 through11 embodiment, the seat is formed by'a resil' ient O-ring member 140carried by an insert 142. As shown, the insert 142 includes a radiallyextending body or flange 144 which is sealingly clamped between thefemale body section 104' and'the inner end of the male body section 102.Preferably, a resilient annular washer or ring I46 is positioned betweenthe insert member 142 and the female body 104. The insert 142 is, in allparticulars, basically identical to the insert 44' described withreference to the FIGS. 1 through 6 embodiment. Additionally, its sizerelationship to the O ring 140 is also the same as discussed withreference to the FIGS. I through 6 embodiment.

The other primary difference between the FIGS. 9 through 11 embodimentand the FIGS. 7 and 8 embodiment is in the arrangement of the adjustingand lock members. In the FIGS. 9 through I] embodiment, the lock member138' is arranged so that it makes only point or line contact with theadjusting member 136.

Note that this is accomplished by grinding a taper on one face of lockmember 138'. That is, the lock memher and the adjusting member arearranged so that their opposed faces are non-parallel. It has been foundthat this prevents transmission of torque from the lock member to theadjusting member. Obviously, other arrangements could be used. Forexample, small protuberances or the like could be formed on one of theother of the opposed faces; the important consideration being theelimination of high frictional engagement between the opposed faces.Otherwise, tightening of the lock could cause changes in the settingpressure.

The invention has been described in great detail sufficient to enableone of ordinary skill in the valve art to make and use the same.Obviously, modifications and alterations of the preferred embodimentwill occur to others upon a reading and understanding of thespecification and it is our intention to include all such modificationsand alterations as part of our invention insofar as they come within thescope of the appended claims.

What is claimed is:

1. A valve comprising:

a valve body including a valve chamber and flow inlet and outletpassages connecting said chamber to inlet and outlet openings;

a seat in said chamber, a valve member continuously biased toward saidseat by spring means; and,

adjustment means for varying the force with which said spring meansbiases said valve member, said adjustment means including an adjustmentmember in engagement with said spring means and threaded in said outletflow passage, a lock member threaded in said outlet flow passage forlocking said adjustment member in desired positions, said adjustmentmember and said lock member having axially aligned flow openings ofsubstantially equal size and non-circular configuration extendingtherethrough with each said flow opening being accessible from saidoutlet opening and the noncircular configuration of said flow openingsproviding means for receiving a tool in said adjustment member and saidlock member whereby adjustment of said valve can be made through saidoutlet opening without disassembly of said valve.

2. The valve as defined in claim 1 wherein said lock member and saidadjustment member have external threads which mate with internal threadsformed in said outlet flow passage.

3. The valve as defined in claim 1 wherein said spring means comprises acoil spring positioned between said valve member and said adjustmentmember.

4. The valve as defined in claim 3 wherein said lock member and saidadjustment member are on the side of said valve member opposite saidseat.

5. The valve as defined in claim 3 wherein said coil spring and saidvalve member are axially aligned with said valve seat.

6. The valve as defined in claim 3 wherein said outlet passage isaxially aligned with said valve chamber and said seat.

7. The valve as defined in claim 1 wherein said outlet passage isaligned with said seat.

8. The valve as defined in claim 1 wherein said means for receiving atool comprise flats formed in said flow openings.

9. The valve as defined in claim 1 wherein said adjustment member andsaid lock member have nonparallel faces which engage over a limited areawhen said lock member is in a lock position.

10. A valve comprising:

a housing having a passage therethrough;

a valve seat means spaced inwardly from a first end of said passage;

a shoulder spaced inwardly from a second end of said passage;

a valve member slidably mounted in said passage between said shoulderand said seat means, said valve member including an end face having aninclined peripheral edge adapted to sealingly engage said seat means anda tubular end extending toward said shoulder and adapted to engage saidshoulder upon predetermined movement away from said seat, spring meansmounted in said passages for maintaining said valve member continuouslybiased to ward said seat means;

said seat means including an axially open, circumferential recess facingsaid end face with and O-ring positioned therein and extending axiallyoutwardly, said recess being defined by the wall of said passage and aninsert member slidably received in said first end of said passage, saidinsert including a center bore and an axially extending flange portionwhich defines the radially inner wall of said recess and terminates inan end, the end of said flange portion having a circumferential lipextending toward the wall of said passage to restrict the axially openend of said recess and tightly enclose said O-ring throughout an extentof greater than degrees of its cross-section to compress said O-ring andcause a portion thereof to extend axially out of said recess forsealingly engaging said peripheral edge, the end of said flange adaptedto engage said end face to limit the compression applied to said O-ringby said valve member;

thread means on said first end for releasably retaining saidinsert'therein; and,

cooperating surfaces on said insert and said wall of said passagebetween said recess and said lock means for limiting axially inwardmovement of said insert and providing a fluid seal between said insertand said wall of said passage.

11. The valve as defined in claim 10 including adjusting means forvarying the compression on said spring means, said adjusting means beingaccessible from the second end of said passage.

12. The valve as defined in claim 11 wherein said adjusting meansincludes a member threaded in the second end of said passage andengaging said spring means.

1 UNITED STATES. PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,75Lh568 Dated August 28, 1973 Invent-Dds) Bernard J. Gallagher et al.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 2, line 2, change "top" to stop Column 3, line 6, change"general" to generally Column 3, line 3L change "incudes" to includes 7Column 3, line 5?, insert 5h after C ring".

Column L line 27, cancel "68".

Column 6, line L change "L 11," to LLO Column 8, line 22, change "and"to an Signed and sealed this 19th day of March l97h.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. c. MARSHALL DANN Attesting Officer Commissioner ofPatents FORM PO-1050 (10-69) USCOMM-DC 60376-P69 k U.$. GOVERNMENYPRINTING OFFICE 2 [99 O'-SG6-33,

1. A valve comprising: a valve body including a valve chamber and flowinlet and outlet passages connecting said chamber to inlet and outletopenings; a seat in said chamber, a valve membEr continuously biasedtoward said seat by spring means; and, adjustment means for varying theforce with which said spring means biases said valve member, saidadjustment means including an adjustment member in engagement with saidspring means and threaded in said outlet flow passage, a lock memberthreaded in said outlet flow passage for locking said adjustment memberin desired positions, said adjustment member and said lock member havingaxially aligned flow openings of substantially equal size andnon-circular configuration extending therethrough with each said flowopening being accessible from said outlet opening and the non-circularconfiguration of said flow openings providing means for receiving a toolin said adjustment member and said lock member whereby adjustment ofsaid valve can be made through said outlet opening without disassemblyof said valve.
 2. The valve as defined in claim 1 wherein said lockmember and said adjustment member have external threads which mate withinternal threads formed in said outlet flow passage.
 3. The valve asdefined in claim 1 wherein said spring means comprises a coil springpositioned between said valve member and said adjustment member.
 4. Thevalve as defined in claim 3 wherein said lock member and said adjustmentmember are on the side of said valve member opposite said seat.
 5. Thevalve as defined in claim 3 wherein said coil spring and said valvemember are axially aligned with said valve seat.
 6. The valve as definedin claim 3 wherein said outlet passage is axially aligned with saidvalve chamber and said seat.
 7. The valve as defined in claim 1 whereinsaid outlet passage is aligned with said seat.
 8. The valve as definedin claim 1 wherein said means for receiving a tool comprise flats formedin said flow openings.
 9. The valve as defined in claim 1 wherein saidadjustment member and said lock member have non-parallel faces whichengage over a limited area when said lock member is in a lock position.10. A valve comprising: a housing having a passage therethrough; a valveseat means spaced inwardly from a first end of said passage; a shoulderspaced inwardly from a second end of said passage; a valve memberslidably mounted in said passage between said shoulder and said seatmeans, said valve member including an end face having an inclinedperipheral edge adapted to sealingly engage said seat means and atubular end extending toward said shoulder and adapted to engage saidshoulder upon predetermined movement away from said seat, spring meansmounted in said passages for maintaining said valve member continuouslybiased toward said seat means; said seat means including an axiallyopen, circumferential recess facing said end face with and O-ringpositioned therein and extending axially outwardly, said recess beingdefined by the wall of said passage and an insert member slidablyreceived in said first end of said passage, said insert including acenter bore and an axially extending flange portion which defines theradially inner wall of said recess and terminates in an end, the end ofsaid flange portion having a circumferential lip extending toward thewall of said passage to restrict the axially open end of said recess andtightly enclose said O-ring throughout an extent of greater than 180degrees of its cross-section to compress said O-ring and cause a portionthereof to extend axially out of said recess for sealingly engaging saidperipheral edge, the end of said flange adapted to engage said end faceto limit the compression applied to said O-ring by said valve member;thread means on said first end for releasably retaining said inserttherein; and, cooperating surfaces on said insert and said wall of saidpassage between said recess and said lock means for limiting axiallyinward movement of said insert and providing a fluid seal between saidinsert and said wall of said passage.
 11. The valve as defined in claim10 including adjustiNg means for varying the compression on said springmeans, said adjusting means being accessible from the second end of saidpassage.
 12. The valve as defined in claim 11 wherein said adjustingmeans includes a member threaded in the second end of said passage andengaging said spring means.